Imido-substituted polyamide compositions

ABSTRACT

POLYAMIDES HAVING TERMINAL ALIPHATICALLY UNSATURATED IMIDO RADICALS ARE PROVIDED AND A METHOD FOR MAKING SUCH MATERIALS. BLENDS OF THE IMIDOSUBSTITUTED POLYAMIDES AND A VARIETY OF ALIPHATICALLY UNSATURATED ORGANIC MONOMERS, SUCH AS STYRENE, N-PHENYLMALEIMIDE, BISMALEIMIDES OR ORGANIC POLYMERS, SUCH AS POLYPHENYLENE OXIDES, POLYVINYL CHLORIDE, POLYSTYRENE, POLYSULFONE, POLYCARBONATE, ETC., ALSO ARE PROVIDED. THE IMIDO-SUBSTITUTED COMPOSITIONS OF THE PRESENT INVENTION CAN BE EMPLOYED AS MOLDING COMPOUNDS, LAMINATES, VARNISHES AND ADHESIVES.

United States Patent Otfice 3,689,464 Patented Sept. 5, 1972 3,689,464 IMIDO-SUBSTITUTED POLYAMIDE COMPOSITIONS Fred F. Holub and Milton L. Evans, Schenectady, N.Y., assignors to General Electric Company No Drawing. Continuation-impart of application Ser. No. 838,315, July 1, 1969. This application Dec. 18, 1970,

Ser. No. 99,653

Int. Cl. C08g 20/20 US. Cl. 260-78 UA 11 Claims ABSTRACT OF THE DISCLOSURE Polyamides having terminal aliphatically unsaturated imido radicals are provided and a method for making such materials. Blends of the imidosubstituted polyamides and a variety of aliphatically unsaturated organic monomers, such as styrene, N-phenylmaleimide, bismaleimides or organic polymers, such as polyphenylene oxides, polyvinyl chloride, polystyrene, polysulfone, polycarbonate, etc., also are provided. The imido-substituted compositions of the present invention can be employed as molding compounds, laminates, varnishes and adhesives.

This application is a continuation-in-part of our copending application Ser. No. 838,315 filed July 1, 1969 now abandoned, and assigned to the same assignees as the present invention.

The present invention relates to polyamide compositions comprising polyamide having chemically combined aliphatically unsaturated imido radicals, such as maleimido radicals, and methods for making such polyamide compositions.

The polyamide compositions of the present invention comprise polyamide having chemically combined aliphatically unsaturated imido radicals of the formula,

where R is an aliphatically unsaturated divalent organo radical selected from hydrocarbon radicals and halogenated hydrocarbon radicals. Included by R of Formula 1 are radicals of the formula,

XzC=(|J-- where W is a group selected from, (a) amide units of the formula,

(b) amide acid units of the formula,

0 0 ll H ll C-NR1N n ,1

' (c) imide units of the formula,

((1) mixtures of (a), (b), or (c), units, and

(e) mixtures of (a), (b), (c), or (d) units, and up to 50 mole percent, based on the total moles of units in the mixture, of amido units selected from,

and mixtures thereof,

where R is a divalent organo radical tree of aliphatic unsaturation selected from hydrocarbon radicals and halogenated radicals, R is a monovalent radical selected from hydrogen, monovalent hydrocarbon radicals and halogenated hydrocarbon radicals, R is a trivalent aromatic organo radical selected from hydrocarbon radicals and halogenated hydrocarbon radicals and R is a tetravalent organic radical containing at least 6 carbon atoms characterized by benzoid unsaturation, wherein the 4-carbonyl groups of the amido units are each attached to separate carbon atoms, and wherein each pair of carbonyl groups is directly attached to adjacent carbon atoms, and y has a value of or 1.

Radicals included by R of Formula 2 are alkylene radicals, such as methylene, ethylene, trimethylene, tetramethylene, etc.; arylene radicals such as phenylene, tolylene, xylene, naphthylene, etc.; halogenated divalent hydrocarbons such as fluoroethylene, chlorophenylene, chloronaphthylene, etc. Radicals included by R are, for example, aryl radicals such as phenyl, naphthyl, xylyl, etc., and alkyl radicals such as methyl, ethyl, propyl, butyl, hexyl, etc. Radicals included by R are trivalent radicals derived from such aromatic hydrocarbons as benzene, xylene, naphthylene, etc., and include, for example, radicals such O: O etc.

Radicals included by R are, for example,

:Q QLLO OEOR OLQ O O limeliand 2 etc.

In the above formulas, where R R R and R can be more than one radical, these radicals can be all the same, or any two or more of the aforementioned radicals.

Some of the carbonamide units of Formula 2, are for example,

Another method of making the imido-substituted polyamides of the present invention, is by effecting reaction between an aliphatically unsaturated anhydride of the formula, (4)

El and an amino-terminated polyamide consisting essentially of chemically combined units of Formula 2, Where R is as previously defined. Included by the aliphatically unsaturated anhydrides of Formula 4 are, for example, anhydride, 3,6 endomethyleue 1,2,3,G-tetrahydrophthalic maleic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, etc.

Among the imido-substituted polyamide compositions of the present invention, there are included imido-substituted polyamides derived from the self-condensation of aminocarboxylic acids, or intercondensation of organodiamines and organo-dicarboxylic acids, etc.; imodo-substituted polyamideimides and polyamide-amide acids resulting from the intercondensation of organic diamines with reactive organic dicarboxylic acid and halides thereof, in combination with chloroformylphthalicanhydride and up to 50 mole percent of the total mixture or organic dianhydride. Some of the imido-substituted polyamides of thelpresent invention are included by the following formu as,

R. R. t that at w all attm. R/

l g g where R, R R and m are as previously defined, M is selected from imido radicals of Formula 1, and

radicals, Q is a divalent organo radical selected from R, R("3-, and R'Oi -R'Otl ll%- n is an integer equal to l to 10, and preferably 5 to 10, a has a value of 0 or 1, b is a whole number equal to 0 or 100, c is a whole number equal to 0 or 100, the sum of b and c can be equal to 1 to 100 and preferably 2 to 50, d is an integer equal to 1 to 100, e is a whole number equal to 0 to 100, is a whole number equal to 0 to 100, the sum of e and f is equal to 1 to100, and preferably 5 to 50, and the sum of d and e and f is equal to 2 to 100, and preferably 5 to 50. 'In Formula 6, g is an integer equal to l to 50, h is a whole number equal to 0 to 50, the ratio of g to the sum of a+g+h, can equal up to /z, and the sum of a+g+h can be equal to 2 to 100' and preferably about 5 to 50.

Included by the polyamides of Formula 2 are polymers derived from self-condensation of amino acids and various diacids and diamines. Some of the diamines which can be employed to make the polyamides utilized in the practice of the invention are, for example, ethylenediamine, m-phenylenediamine, p,p'-diaminodiphenylmethane, hexamethylenediamine, piperazine, and diamines having the formula,

where I is selected from C alkylene Some of the diacids or diacidchlorides which can be employed to make the polyamides of the present invention are, for example, oxalic acid, adipic acid, and isophthalic acid, azelaic acid, etc. As previously indicated, the polyamides of the present invention can be made by direct amidation of amine groups with carboxyl groups accompanied by an elimination of water. In addition, the polyamides utilized in the present invention also can be made by reaction of acid chlorides, such as condensation of diamines and diacid chlorides. Polymerization based on ring openings, such as polymerization of caprolactam, etc.

Among the aromatic polyamides which can be employed in the practice of the present invention are aromatic polyamides derived by the intercondensation of aromatic dicarboxylic acids such as teraphthalic acid, isophthalic acid, with organo diamines such as m-phenylenediamine, 2,4-diaminotolylene, bis(4-aminophenyl)methane, and hexamethylene diamine. In addition, the aforementioned organo diamines can be reacted with 4-chloroformylphthalic anhydride and up to 50 mole percent of organic dianhydrides based on the total moles of reactants, to provide for the production of a polyamide having chemically combined amide acid and imide units. Some of the dianhydrides include, for example, benzophenone dianhydride (e.g., 2,2',3,3- 2,3,3,4'- 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride), pyromellitic dianhyrdride, ethylene glycol bis trimellitate anhydride, etc.

The imido-substituted polyamides of the present invention can be used as molding compounds, varnishes, etc., when utilized with an organic solvent such as dimethylformamide N-methylpyrrolidone, etc. The imido-substituted polyamides also can be made into solvent-resistant coating compositions by exposure to high energy electron irradiation by curing with peroxides or other free radicals initiators as described below or by heat. The imido-substituted polyamide acids shown for Formula 2 and illustrated by Formulas 4, 5 and 6 also can be electrocoated onto an electrically conducting substrate when the substrate is immersed in the polyamide acid and an electric current is passed through the polyamide acid.

The imido-substituted polyamides of the present invention can be blended with various aliphatically unsaturated organic materials such as aliphatically unsaturated organic monomers and certain organic polymers, as well as organic polymers free of aliphatic unsaturation. Blends of the imido substituted polyamides and the aforementioned organic monomers or polymers can be made over wide proportions by weight. Experience has shown that there can be employed in the blend at least about 5 percent to percent by weight, and preferably from 10 to 40 percent by weight of the imido-substituted polyamide based on the total blend weight to provide for cured products exhibiting such valuable characteristics as solvent resistance, toughness, resistance to deformation at elevated temperatures, etc. Depending upon the proportion of the imido-substituted polyamide in the organic polymer or monomer, the blends can provide for laminates, varnishes, molding compounds, coating compositions, etc.

The aliphatically unsaturated organic monomers which can be employed in combination with the imido-substituted polyamides include, for example, N,N'-p,p'-diphenylmethanebismaleimide, styrene, chlorostyrene, diallyphthalate, vinylchloride, isobutylene, butadiene, isoprene, chlorotrifiuoroethylene, Z-methylpentyne-l; vinyl esters of organic carboxylic acids such as vinyl formate, vinylacetate, acrylonitrile, etc.; esters of acrylic and methacrylic acids, etc.; divinylbenzene, triallylcyanurate, triallylisocyanurate, vinylphthalimide, N-allylphthalimide, reaction products of diamines and N,N-arylene or alkylene bismaleimides, N- allyltetrachlorophthalimide, etc. Among the organic polymers that can be employed in combination with the imidosubstituted polyamides of the present invention are, for example, polyvinylchloride, polyphenylene oxides, polypropylene, polysulfones, polyarylsulfone ethers, epoxy resins, phenolformaldehyde resins, organo polysiloxanes, polyesters, polycarbonates, acrylonitrile-butadiene-styrene copolymers, styrene-butadiene block polymers, etc.

The blend of the imido-substituted polyamide and the aforementioned organic monomers or polymers, can be cured with conventional free radical initiators at temperatures of from 50 C. to 250 C., while 100 C. to 200 C. has sometimes been found to be more desirable. Acceleration of the cure can be achieved with organic peroxides, such as dicumyl peroxide, benzoyl peroxide, tertiary butylperbenzoate, tertiary alkylperoxycarbonate, azodicarbonamides, 2,5-dimethyl-2,5-bis(tert-butylperoxyhexane), etc. The peroxides can be employed from about 0.1 percent to about percent by weight, based on the total weight of the blend. In addition, the imido-substituted polyamides or blends thereof, in addition to being curable by the aforementioned free radical initiators, can be cured with heat or radiation with high electrons, X-rays, ultraviolet light, etc.

One of the methods of making the imido-substituted polyamides of the present invention involves effecting reaction between the imido-substituted compound, such as shown by Formula 3 and the polyamide consisting essentially of chemically combined units of Formula 2 utilizing an organic solvent at temperatures in the range of between 25 C. to 250 C. and preferably 30 C. to 45 C. Any suitable solvent can be employed to facilitate the formation of the imido-substituted polyamide, which are inert to the reactants under the conditions of the reaction. For example, there can be employed such solvents as N-methylpyrrolidone, dimethylformamide, dimethylacetamide, etc.

The type of imido compound of Formula 3 used to incorporate imido radicals of Formula 1 into the polyamide will generally be influenced by the nature of the terminal groups of polyamide used, which can include, for example, such terminal groups as amino groups, carboxy groups, hydroxy groups, amide acid groups, imide groups, etc. In addition, when employing an imido-substituted acylhalide in combination with the polyamide, an acid acceptor such as pyridine, triethylamine can be utilized to facilitate the formation of the imido-substituted polyamide.

In addition to the aforementioned aliphatically unsaturated monomers and organic polymers which can be employed with the imido-substituted polyamides, there also can be employed by weight proportions of from 0 to 100 parts per 100 parts of the imido-substituted polyamide, fillers such as treated with clay, ground quartz,

glass beads, film silica, sand, carbon black, glass fibers, quartz fibers, carbon fibers, asbestos, etc. In addition, other ingredients can be employed such as solvents, etc., at from 60 percent to 90 percent by weight of the re- '8 sulting curable composition. For example, there can be used N-methylpyrrolidone, dimethylacetamide, and plasticizers such as trioctyltrimellitate, chlorinated biphenyl, etc.

In order that those skilled in the art will be better able to practice the present invention, the following examples are given by way of illustration and not by way of limitation. All parts are by weight.

EXAMPLE 1 There was added 5.2 parts of a diamine having the formula,

to a mixture of 1.96 parts of maleic anhydride and 30 parts of dimethylformamide in a Dry Ice acetone bath at &-20 C. After the addition was complete, the mixture was allowed to warm to room temperature and one part of fused anhydrous sodium acetate and 10 parts of acetic anhydride were added. The mixture was then stirred for about 12 hours. The mixture was then poured into water effecting the precipitation of a solid that was filtered and dried in vacuo at C.

Based on method of preparation and its infrared spectrum, the product was a maleimidoterminated polyamide having the formula,

A film of the above maleimido-terminated polyamide was cast from a solution of N-metbylpyrrolidone containing 4 percent by weight of dicumyl peroxide based on the weight of the solids. The film was cured at C. for /2 hour and 200 C. for /2 hour. The film did not melt up to 300 C. and was insoluble and resisted swelling in N-methylpyrrolidone. When placed between 2 conducting wires having a diameter of about 50 mil under a 1,000 gram weight, in accordance with the test procedure of Precopio et al., Pat. 2,936,296, the film was found to have a cut-through of 330 C. Based on these results, one skilled in the art would know that the solution blend of the maleimido-terminated polyamide and peroxide can provide for valuable solvent resistant films and coatings useful in dielectric and insulating applications.

EXAMPLE 2 A mixture of 5.2. parts of the diamine of Example 1, 4.71 parts of p-maleimidobenzoylchloride, 40 parts of dimethylformamide and 2 parts of pyridine was stirred under a nitrogen atmosphere. An exothermic reaction occurred when the reactants were combined and stirred. After stirring the mixture for 1 hour, it was poured into water which effected the precipitation of a gray-brown solid. It was filtered and dried in vacuo at 80 for about 12 hours. Based on method of preparation, and its infrared spectrum, the product was a maleimido-terminated polyamide having the formula,

ill

A film of the above maleimido-terminated polyamide was cast from N-methylpyrrolidone in accordance with the procedure of Example 1. The film was cured at 150 C. for /2 hour and 200 C. for /2 hour. The cured film had a melting point greater than 400 C. and was insoluble in N-methylpyrrolidone. The film had valuable solvent resistant properties and can be employed as a highperformance insulating coating material on metallic and nonmetallic substrates.

EXAMPLE 3 There was added to a mixture of 9.9 parts of methylene dianiline and 70 parts of dry dimethylacetamide at a temperature of 4 C. under a nitrogen atmosphere, 4.71 parts of p-maleimide benzoylchloride and '6.42 parts of 4 chloroformylphthalic anhydride. An immediate exothermic reaction occurred which resulted in an exotherm to 45 C. The resulting mixture was stirred for two hours under nitrogen. The mixture was then poured into methanol to elfect the precipitation of the product which was dried in vacuo at 70 C. for about 12 hours. Based on method of preparation and nitrogen analysis, the product was a maleimido-terminated polyamide acid-amide having the formula,

where n has the approximate average value of 4.

A 20 percent solids solution in N-methylpyrrolidone containing about 2 percent by weight of dicumyl peroxide was used to cast a film on an aluminum substrate. The

film was cured at 125 C. for one hour and 200 C. for

EXAMPLE 4 There was added to a mixture of 9.9 parts of p,p'- methylene dianiline and 70 parts of dry dimethylacetamide at a temperature of about 4 C. under nitrogen, 4.71 parts of p-maleimidobenzoylchloride and 8.12 parts of isophthaloyl chloride while the mixture was stirred. The temperature of the mixture rose to 70 C. and it was stirred for an additional two hours under nitrogen after the addition was completed. The mixture was then poured into methanol to effect the precipitation of the product which was filtered and dried in vacuo at 7 C. for about 12 hours. Based on method of preparation and nitrogen analysis, the product was a maleimide-terminated polyamide having the formula,

where n has the approximate average value of 4.

In accordance with the above-described procedure, a film was cast from a 20 percent N-methylpyrrolidone solution of the above maleimide-terminated polyamide containing 2 percent by weight of dicumyl peroxide. The film was cured at 125 C. for one hour and 200 C. for one hour. It had a cut-through of 345 C. based on the tests described in Example 1 and it was insoluble in N- in the art would know that the polyamide having terminal maleimido radicals could provide for the production of high temperature laminating compounds.

EXAMPLE 5 There was added to a mixture of 9.9 parts of p,pmethylene dianiline, 70 parts of dry dimethylacetamide maintained at a temperature of 4 C. under a nitrogen atmosphere, 4.71 parts of p-maleimidobenzoyl chloride, 4.06 parts of isophthaloyl chloride and 3.21 parts of 4- chloroformylphthalic anhydride. Upon the addition of the aforementioned ingredients, the mixture exothermed to a temperature of 50 C. The mixture was then stirred for an additional 2 hours under nitrogen after the addition was completed. The mixture was then poured into methanol to effect the precipitation of the product. The product was dried in vacuo at 70 C. for a period of 12 hours. Based on method of preparation and nitrogen analysis, the product was a maleimido-terminated poly amide acid-amide consisting of chemically combined units of the formulas,

A 20 percent solution of the above maleimidoterminated poyamide acid-amide containing 2 percent by Weight of dicumyl peroxide in N-methylpyrrolidone was used to cast a film on aluminum substrate. The film was cured at a temperature of 125 C. for 1 hour and 200 C. for 1 hour. After the cure, a tough, flexible film was produced having a cut-through of 280 C. which was insoluble in N-methylpyrrolidone. Based on the aforementioned properties, those skilled in the art would know that the maleimide-terminated polyamide acid-amide would be useful as a wire enamel and an electrical insulator on copper wire.

EXAMPLE 6 A blend of 33 parts of the maleimide-terminated polyamide of Example 1, 65 parts of methylene dianilinebismaleimide and 2 parts of dicumyl peroxide was made in the form of a solution in N-methylpyrrolidone containing about 20 percent solids by weight. A film was cast from the blend on an aluminum substrate. The film was cured methylpyrrolidone. Based on the properties, one skilled for 1 hour at C. and 1 hour at 200 C. A valuable self-supporting solvent resistant insulating film was obtained having a cut-through of 375 C.

EXAMPLE 7 A film was cast on an aluminum substrate from an N-methylpyrrolidone solution of a 20 percent solids by Weight blend of 33 parts of the maleimido-terminated polyamide acid of Example 1, 65 parts of a poly(2,6-dimethylphenylene oxide) having an intrinsic viscosity in chloroform at 25 of 0.49 and 2 parts of dicumyl peroxide. The film was cured for 1 hour at 125 C. and 1 hour at 200 C. The film was found to be a tough, selfsupporting material having a cut-through of about 183 C. as compared to 142 C. for the cured poly(phenylene oxide) free of the M-terminated polyamide.

EXAMPLE 8 In accordance with the procedure of Example 7, a film was cast on aluminum substrate from a 20 percent solids N-methylpyrrolidone solution of a blend of 33 parts of the maleimide-terminated polyamide of Example 1, 65 parts of polyvinylchloride (Germ-101) and 2 parts of dicumyl peroxide. The film was cured for 1 hour at 125 C., and 1 hour at 200 C. A tough film was obtained which was insoluble in N-methylpyrrolidone. It had a cut-through of 285 C. Based on these results, the curable blend was valuable as a compound useful for making a solvent resistant coating.

EXAMPLE 9 There was added with stirring to 45 parts of N-methylpyrrolidone, 4.62 parts of 1,6-hexamethylene diamine and 3.65 parts of isophthaloyl chloride. An exothermic reaction occurred. There was then added 7.6 parts of pyridine, followed by 5.8 parts of benzophenone dianhydride and 0.98 part of 3,6-endomethylene 1,2,3,6-tetrahydrophthalic anhydride. The resulting mixture was a clear solution which was allowed to stir for 30 minutes.

The mixture was allowed to cool to room temperature and 20 parts of water was added. The mixture was then poured into 2000 parts of water. There was added 20 parts of 88% formic acid which efi'ected the precipitation of a white solid. The mixture was filtered, and the filtrate was washed and air dried. Based on method of preparation, the product was a polyamide having terminal aliphatically unsaturated radicals and the approximate average formula,

H if

H O O O l H n u H H CH2 N(CH2)uN-O ON(OH2)uNC- i H C/ HO. C 1'1 45 H where n has an average value of about 2.

One part of the above polymer was mixed with 2 parts of N-methylpyrrolidone at room temperature to produce a varnish having about 33% solids. The varnish was poured into an aluminum metal foil and heated for 10 minutes at 250-280 C. A tough flexible film was obtained which adhered well to the aluminum substrate. It did not soften at temperatures up to 250 C.

The above varnish is employed as an enamel on 50 mil copper wire by conventional dip coating means. Three layers of enamel being formed by dipping the wire into the varnish and curing for 5 minutes at 300 C. before each dip. The enamel exhibits superior cut-through resistance employing the test described in Precopia et 211., Pat. 2,936,296.

The same procedure is repeated except aluminum wire is substituted for the copper wire, and substantially equivalent results are achieved.

EXAMPLE 10 Reaction was effected at a temperature in the range of 150 C.200 C. between 198 parts of p,p'-methylenedianiline and 94 parts of azelaic acid in the presence of 40 parts of mineral spirits. The mixture was heated over a period of about 2 hours, and 17.5 parts of water were evolved. The mixture was then stripped of hydrocarbon solvent and a diamide in the form of a yellow solid was obtained at quantitative yield.

There was added 3.22 parts of benzophenone dianhydride to a mixture of 30.1 parts of n-methyl pyrrolidone and 6.58 parts of the above diamide. The mixture was stirred and a clear viscous solution was obtained. After the mixture had cooled to room temperature, there was added 3.92 parts of maleic anhydride, which produced a clear varnish upon stirring.

The above varnish was cast onto an aluminum substrate and heated for 10 minutes at a temperature between 200 C.-270 C. There was obtained a tough flexible film.

The above varnish was evaluated as a wire enamel for copper and aluminum in accordance with the procedure of Example 9. The resulting film exhibited superior cut through properties.

EXAMPLE 11 There was added 48 parts of trimellitic anhydride to a mixture of 49.5 parts of p,p'-methylenedianiline, 100 parts of N-methyl pyrrolidone, and 35 parts of xylene. The mixture was heated at 190 C. for minutes resulting in the production of a water and xylene azeotrope which was separated from the mixture. The mixture was then allowed to cool to below C., and there were added 49.5 parts of p,p'-methylenedianiline and 32.75 parts of amino caproic acid. The mixture was heated at 190 C. for minutes and then cooled to C. There was then added 81 parts of 3,6 endomethylene 1,2,3,6-tetrahydrophthalicanhydride along with 30 parts of N-methylpyrrolidone. The mixture was stirred for an additional hour at C. until no further water was separated.

The mixture was then poured into 478 parts of N- methylpyrrolidone to produce a clear solution containing 30% solids. The solution was then poured onto an aluminum substrate. After 5 minutes at a temperature beo o 0 II II E l o o monmN H2 2011 (J H o u 0 tween 250 C. and 300 C., there was obtained a cured film exhibiting valuable insulating properties.

A further method of making the imido-substituted polyamides of the present invention is by employing an imidoalkylene compound such as the hydroxide or chloride in the presence of a Friedel-Crafts catalyst such as boron trifluoride, in accordance with the method of Klebe and Windish, Ser. No. 846,623, filed July 1, 1969, and assigned to the same assignee as the present invention. Although the preceding examples are limited to only a few of the many imido-substituted polyamides included by the present invention, it should be understood that the present invention is directed to a much broader class of imido-substituted polyamides, where the N atom of such imido radicals either can be directly joined tothe polyamide in the terminal position or along the polymer backbone.

13 What is claimed is: 1. An imido substituted polyaryleneamide which has terminal imido radicals of the formula,

and which consists essentially of chemically combined carbonamide units of the formula,

least 6 carbon atoms characterized by benzoid unsaturation, wherein 4 carbonyl radicals are each attached to separate carbon atoms, and wherein each pair of carbonyl groups is directly attached to adjacent carbon atoms, and y is a whole number having a value of or 1. 2. An imido-substituted polyamide acid composition in accordance with claim 1 having terminal imido radicals which consists essentially of aryltricarboxylic acid units chemically combined with diarylamino units.

3. A polyamide acid composition in accordance with claim 1, having from 2 to 500 chemically combined units. 4. A maleimido-terminated polyamide in accordance with claim 1.

ll 5. A polyamide in accordance with claim 1, of the foru Q Q NC m n 0-0 0-0 E ii n 1 H where T is a group selected from the class consisting of,

'(a) amide units of the formula,

(b) amide acid units of the formula,

(c) imide units of the formula,

0 II ..m N...

(d) mixtures of (a), (b), or (c), and (e) mixtures of (d) units and up to 50 mole percent, based on the total moles of units in the mixture of amido units selected from 0 'E l \R'/ and \R4 \N 1100 \COH HOC/ o ll ii where n is an integer equal to from 2 to 500.

6. A polyamide acid in accordance with claim 2, of the formula,

-E OH 5 where n is an integer equal to from 2 to 500.

7. A polyamide in accordance with claim 1, of the formula,

8. A polyamide in accordance with claim 1, of the formula,

EC 0 it 9. A polyamide in accordance with claim 1, having terminal imido radicals of the formula,

c it which consists essentially of chemically combined amido units of the formula,

joined by hexamethylene radicals.

essentially of chemically combined units of the formula,

and terminal units selected from and Jana

11. The solvent resistant polyarylene amide obtained 10. A polyamide in accordance with claim 1, consisting by curing at a temperature; in the range of C. to 250 C. the polyamlde of claim 1 utilizing a free radical initiator.

References Cited UNITED STATES PATENTS HAROLD D. ANDERSON, Primary Examiner US. Cl. X.R.

117-9331, 161 P, 161 UA; 260-30.2, 31.8 B, 32.6 N, 41 R, 47 UA, 47 CZ, 65, N, 78 A, 78 TF, 824 R, 841, 857 UN, 857 R, 860, 873 

